Pumping device

ABSTRACT

A pumping device may include a drive device coupled to a feed element via a hydrostatic coupling. The hydrostatic coupling may be configured to control a torque transmission between the drive device and the feed element. The hydrostatic coupling may include a suction side connected to a pressure side via a coupling-fluid-carrying channel. A valve device may be arranged in the coupling-fluid-carrying channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application No. 102012 213 985.0, filed Aug. 7, 2012, and International Patent ApplicationNo. PCT/EP2013/066504, filed Aug. 6, 2013, both of which are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a pumping device with a drive devicefor driving a feed element of the pumping device according to theintroductory clause of claim 1.

BACKGROUND

From EP 2 386 773 A2 a generic pumping device is known with a drivedevice for driving a feed element of the pumping device and with agerotor coupling, by means of which a torque transmission between thedrive device and the feed element is controllable. Through the couplingdevice which is uncoupled in such a manner, it is possible to not onlytransmit the full driving torque from the drive device to the feedelement, but alternatively also any desired partial torques, this beingwithout the wear phenomena occurring in conventional couplings, forexample by a grinding of the coupling discs.

From EP 1 736 669 A2 a further pumping device is known in the manner ofa controllable coolant pump for internal combustion engines, by way ofwhich the coolant temperature can be regulated continuously in adependent precise and smooth manner. The coolant pump has here a pumpshaft mounted in a pump bearing in the bearing housing, a seal sealingthe bearing chamber from the pump chamber, and a freely rotatable pumpwheel arranged on a sliding bearing of the pump shaft, which pump wheelis driven by a coupling, arranged on the pump shaft, as a function ofthe temperature of the coolant. In this case, the coupling is alsoconstructed as a gerotor coupling.

From DE 2 031 508 A1 a drive is known, operating according to thehydraulic principle, for example the gerotor principle. Here, a vacuumpump is driven by a hydraulic machine, by a fluid flow being directedthrough the hydraulic machine.

SUMMARY

The present invention is concerned with the problem of indicating for apumping device of the generic type an improved embodiment, which isdistinguished in particular by an exact and structurally simple control,independent of the direction of rotation and independent of the rotationspeed.

This problem is solved according to the invention by the subject matterof the independent claim 1. Advantageous embodiments are the subjectmatter of the dependent claims.

The present invention is based on the general idea of providing ahydrostatic coupling, for example a gerotor coupling, in a pumpingdevice known per se, for example an oil pump, a water pump, a vacuumpump or a fuel pump in a motor vehicle, between a drive device and afeed element of the pumping device, for example an impeller, by means ofwhich hydrostatic coupling a torque transmission between the drivedevice and the feed element is able to be easily controlled orregulated. Coming into consideration as drive device is a further pump,the drive shaft of which is also used, a belt pulley, a toothed wheel, achain wheel or a similar drive element. In order to enable here acontrol or regulation of the torque transmission in the hydrostaticcoupling which is on the one hand structurally simple, but on the otherhand is also exact, a suction side and a pressure side of the gerotorcoupling are connected to one another by way of acoupling-fluid-carrying channel, wherein the coupling-fluid-carryingchannel is itself flowed through by a coupling fluid, for example byoil, and wherein in the coupling-fluid-carrying channel a valve deviceis arranged. In fact, mention is usually made in the following to agerotor coupling, wherein it is clear that of course this is to beunderstood to mean in general a hydrostatic coupling. Such a valvedevice can have, for example, an adjustable piston which according toposition controls a through flow through the valve device and hence alsoa torque transmission of the gerotor coupling. Through the valve deviceaccording to the invention it is therefore possible to control a torquetransmission in the gerotor coupling on the one hand in a structurallysimple manner and on the other hand extremely exactly, so that not onlyan opening and closing of the gerotor coupling is possible, but also atransmission of merely partial torques. If therefore, for example, thedrive device of the pumping device is switched on and transmits via adrive shaft a torque to an inner toothed wheel of the gerotor coupling,a torque transmission thus takes place in a pressure-dependent mannerfrom the fluid situated in the gerotor coupling to the outer ring andtherefore a torque transmission to the feed element of the pumpingdevice. If the full torque is to be transmitted to the feed element, thevalve device in the coupling-fluid-carrying channel is blocked,whereupon the pressure of the fluid conveyed by the gerotor couplingincreases and thereby closes the coupling. Through the increasingpressure, the torque is now transmitted from the drive device via acorresponding shaft to an inner toothed wheel and from the latter to theouter ring. Ideally, the pressure side of the gerotor pump is completelysealed here, so that the drive torque can be transmitted completely tothe feed element via the fluid enclosed in the chamber, for example oil.

In an advantageous further development of the solution according to theinvention, the coupling-fluid-carrying channel is connected with thechannel duct of the main oil pump of the internal combustion engine andis therefore integrated into the oil circuit of the internal combustionengine.

In an advantageous further development of the solution according to theinvention, the valve devices and the gerotor coupling are able to beflowed through and used forwards and backwards. In this case, comparedwith couplings known from the prior art, the coupling is therefore ableto be used in both rotation directions, so that the pumping device canrun purely theoretically forwards or backwards and in both rotationdirections a variable adjusting of a transmittable torque is possible atthe gerotor coupling.

Expediently, the valve device has an adjustable piston which, accordingto position, controls a through-flow through the valve device andtherefore the torque transmission of the gerotor coupling. For adjustingthe piston of the valve device, a setting device is provided here, whichis configured in particular as a wax expansion element, a hydraulicsetting device, a pneumatic setting device, an electrical setting deviceor a vacuum box. The multiplicity of the said possible embodiments ofthe possible setting devices already suggests how flexibly thehydrostatic coupling according to the invention is able to be used.

In a further advantageous embodiment of the solution according to theinvention, the gerotor coupling is integrated into a housing of thepumping device. Hereby, a particularly compact structural form can beachieved, which is of great advantage in particular in modern andcramped engine compartments.

Expediently, the piston of the valve device is prestressed by means of aspring into a position closing the valve device. Such a spring is usedto realize a so-called “fail-safe function”, so that on failure of thesetting device the spring makes provision that the valve device closesand therefore likewise the gerotor coupling is also closed. With aclosed gerotor coupling, a full torque transmission takes place from thedrive device to the feed element and therefore a maximum possibleconveying capacity of the pumping device, connected with the outputside, which is of great advantage in particular in the construction as acoolant pump, because thereby an overheating of an internal combustionengine can be avoided.

Further important features and advantages of the invention will emergefrom the subclaims, from the drawings and from the associated figuredescription with the aid of the drawings.

It shall be understood that the features mentioned above and to beexplained further below are able to be used not only in the respectivelyindicated combination, but also in other combinations or in isolation,without departing from the scope of the present invention.

Preferred example embodiments of the invention are illustrated in thedrawings and are explained in further detail in the followingdescription, wherein identical reference numbers refer to identical orsimilar or functionally identical components.

BRIEF DESCRIPTION OF THE DRAWINGS

There are shown here, respectively diagrammatically,

FIG. 1 an illustration of a possible embodiment of a gerotor couplingaccording to the invention,

FIG. 2 a sectional illustration through a pumping device according tothe invention, with gerotor coupling,

FIG. 3 a pumping device according to the invention in the manner of anoil pump,

FIG. 4 a sectional illustration along the section plane B-B of FIG. 3,

FIG. 5 a sectional illustration through a pumping device constructedaccording to the invention as a water pump.

DETAILED DESCRIPTION

In accordance with FIGS. 2 to 5, a pumping device 1 according to theinvention has a drive device 2 for the driving of a feed element 3, forexample of an impeller 4 (cf. FIG. 5) of the pumping device 1. In orderto enable as fine a controlling or respectively regulating of thepumping device 1 as possible with regard to its conveying capacity, ahydrostatic coupling 5, in particular a gerotor coupling 5′ (cf. alsoFIG. 1) is provided, by means of which a torque transmission between thedrive device 2 and the feed element 3 is able to be influenced. Thepumping device 1 can be configured here for example as an oil pump (cf.FIGS. 3 and 4) or as a water pump (cf. FIG. 5) or else as a fuel pump.

In the gerotor coupling 5 according to the invention, a suction side 6and a pressure side 7 are connected with one another by way of acoupling-fluid-carrying channel 8, wherein a valve device 9 is arrangedin the coupling-fluid-carrying channel 8. If one observes the valvedevice 9 more closely, it can be seen that the latter has an adjustablepiston 10, which according to position controls a through-flow throughthe valve device 9 and therefore a torque transmission of the coupling5,5′. Also, a setting device 12 is provided for adjusting the piston 10of the valve device 9, which can be configured in particular as a waxexpansion element, a hydraulic setting device, a pneumatic settingdevice, for example as an under box. The setting device 12 isoperatively connected here with the piston 10. A spring 11 is alsoprovided, by means of which the piston 10 is prestressed into a positionclosing the valve device 9, wherein with closed valve device 9, duringan operation of the pumping device 1 a build-up of pressure takes placein the coupling 5,5′, whereby a full torque transmission can be ensuredfrom the drive device 2 to the feed element 3. This is of greatadvantage in particular in a pumping device 1 configured as a coolantpump, because hereby an overheating for example of an internalcombustion engine can be prevented.

If one observes the gerotor coupling 5′ of FIG. 1 more closely, it canbe seen that it is able to be flowed through in both directions, i.e.both forwards and backwards, just as an associated valve device 9 whichis to be adapted, so that generally the entire pumping device 1 can beoperated both in a forwards operation and also in a backwards operation.

According to FIG. 1 the gerotor coupling 5′ has a drive shaft 13,connected with the drive device 2 which is not shown, which drive shaftin this case brings about a torque transmission to an outer ring 14.Furthermore, an inner ring 15 is provided, which has at least one toothless than the outer ring 14 and together with the outer ring 14 enclosesa displacement volume 16. Here, either the inner ring 15 or the outerring 14 can be mounted eccentrically. The inner ring 15 is connected byway of a torque-proof connection, for example a form-fitting orforce-fitting connection, with the feed element 3, for example by way ofa shaft 17.

As can be further seen from FIG. 1, the inner ring 15 is mountedeccentrically to the outer ring 14. Generally, of course, the inner ring15 can also be connected in a torque-proof manner with the drive device2, wherein then the outer ring 14 is connected in a torque-proof mannerwith the feed element 3.

Observing FIG. 2, the coupling 5,5′ can be seen in a possibleembodiment, wherein the reference numbers are largely taken over fromFIG. 1. In order to obtain as full a torque transmission as possiblewith a closed valve device 9, a gap seal 18 is provided, by means ofwhich an undesired bypass flow and hence a loss of pressure in thedisplacement volume 16 can be prevented. At the same time, a slidingbearing 20 to a housing 19 takes place in this region. Observing FIGS. 3and 4, the gerotor coupling 3 according to the invention can be seen ina pumping device 1 configured as an oil pump, wherein in particular inFIG. 4 the sliding bearing 20 is again readily visible.

In FIG. 5 a pumping device 1, configured as a water pump, isillustrated, with a feed element 3 configured as an impeller, with aseal 21, which seals the water pump with respect to the coupling 5,5′,and with a housing 19, into which the coupling 5,5′ is integrated. Thecoupling 5,5′ has again here an inner ring 15, an outer ring 14 and abearing 22 for bearing the drive shaft 13. A cover plate 23 isadditionally provided.

The pumping device 1 can be controlled particularly exactly and in aproblem-free manner with the coupling 5,5′ according to the invention.

The principle which has been explained can also be transferred in ananalogous manner to an internal gear pump, an external gear pump, avane-type pump and a pendulum slide cell pump (PSC).

1. A pumping device, comprising: a drive device coupled to a feedelement via a hydrostatic coupling the hydrostatic coupling configuredto control a torque transmission between the drive device and the feedelement, the hydrostatic coupling including a suction side connected toa pressure side via a coupling-fluid-carrying channel, wherein a valvedevice is arranged in the coupling-fluid-carrying channel.
 2. Thepumping device according to claim 1, wherein the pumping device is atleast one of an oil pump, a vacuum pump, a water pump and a fuel pump.3. The pumping device according to claim 1, wherein the valve device hasan adjustable piston, which is moveable between a closed position and anopened position to control a through-flow of a fluid through the valvedevice thereby controlling the torque transmission of the hydrostaticcoupling.
 4. The pumping device according to claim 3, wherein the pistonis prestressed via a spring into a position closing the valve device. 5.The pumping device according to claim 1, wherein the valve device andthe hydrostatic coupling are operable to communicate a through-flow of afluid in a first fluid flow direction and a second fluid flow directionopposite the first fluid flow direction.
 6. The pumping device accordingto claim 2, wherein the coupling-fluid-carrying channel is integratedinto a channel duct of the oil pump of an internal combustion engine. 7.The pumping device according to claim 1, wherein the hydrostaticcoupling operates according to at least one of a gerotor principle, aninternal gear pump principle, an external gear pump principle, apendulum slide cell pump principle and a vane-type pump principle. 8.The pumping device according to claim 3, further comprising a settingdevice for adjusting the piston of the valve device, the setting deviceconfigured as at least one of a wax expansion element, a hydraulicsetting device, a pneumatic setting device, an electrical setting deviceand a vacuum box.
 9. The pumping device according to claim 1, whereinthe hydrostatic coupling is integrated into a housing of the pumpingdevice.
 10. The pumping device according to claim 1, wherein thehydrostatic coupling includes at least one component mountedeccentrically thereon to enclose a displacement volume.
 11. The pumpingdevice according to claim 1, wherein the torque transmission in thehydrostatic coupling occurs via at least one of mechanically andhydraulically thereby resulting in an increase in rotation speed of anoutput shaft connected to the feed element with respect to a drive shaftconnected to the drive device.
 12. The pumping device according to claim1, wherein the hydrostatic coupling includes an inner ring mountedeccentrically with an outer ring, the inner ring and the outer ringdefining a displacement volume therebetween for receiving a fluid. 13.The pumping device according to claim 2, wherein the valve device has anadjustable piston configured to transition between an opened positionand a closed position to control a through-flow of a fluid through thevalve device.
 14. The pumping device according to claim 3, furthercomprising a setting device for adjusting the piston of the valvedevice.
 15. The pumping device according to claim 3, wherein the valvedevice and the hydrostatic coupling are operable to communication athrough-flow of a fluid in a first fluid flow direction and a secondfluid flow direction opposite the first fluid flow direction.
 16. Thepumping device according to claim 15, further comprising a settingdevice for adjusting the piston of the valve device, the setting deviceincluding at least one of a wax expansion element, a hydraulic settingdevice, a pneumatic setting device, an electrical setting device and avacuum box.
 17. The pumping device according to claim 5, wherein thehydrostatic coupling is integrated into a housing of the pumping device.18. The pumping device according to claim 17, wherein thecoupling-fluid-carrying channel is integrated into a channel duct of anoil pump.
 19. The pumping device according to claim 6, wherein thehydrostatic coupling is integrated into a housing of the pumping device.20. A pumping device, comprising: a drive device coupled to a feedelement via a hydrostatic coupling, the hydrostatic coupling including asuction side connected to a pressure side via a channel configured tocommunication a coupling fluid, wherein the hydrostatic coupling isconfigured to control a torque transmission between the drive device andthe feed element; a valve device arranged in the channel for controllinga through-flow of the coupling fluid through the channel, the valvedevice including an adjustable piston configured to transition between aclosed position blocking the through-flow and an opened positionpermitting the fluid flow, wherein the piston is prestressed into theclosed position via a spring; and wherein the valve device and thehydrostatic coupling are configured to communicate the through flow ofthe coupling fluid in a first direction and a second direction oppositethe first direction.